RTA_FLOW
[RTA_FLOW] = { .type = NLA_U32 },
case RTA_FLOW:
nla = nla_find(attrs, attrlen, RTA_FLOW);
if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
nla = nla_find(attrs, attrlen, RTA_FLOW);
nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))